Blue luminescence of SrTiO3 under intense optical excitation

Abstract

The blue-green photoluminescence emitted by pure and electron-doped strontium titanate under intense pulsed near-ultraviolet excitation is studied experimentally, as a function of excitation intensity and temperature. Both emission spectra and time-resolved decays of the emission are measured and analyzed in the framework of simple phenomenological models. We find an interesting blue-to-green transition occurring for increasing temperatures in pure samples, which is instead absent in doped materials. The luminescence yield and decay rate measured as a function of temperature can be modeled well as standard activated behaviors. The leading electron-hole recombination process taking place in the initial decay is established to be second-order, or bimolecular, in contrast to recent reports favoring a third-order interpretation as an Auger process. The temporal decay of the luminescence can be described well by a model based on two interacting populations of excitations, respectively identified with interacting defect-trapped (possibly forming excitons) and mobile charges. Finally, from the measured doping and sample dependence of the luminescence yield, we conclude that the radiative centers responsible for the luminescence are probably intrinsic structural defects other than bulk oxygen vacancies.

References in corpus (5)

• Electron-phonon interaction and charge carrier mass enhancement in SrTiO3
• Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation
• Coherent and Incoherent States of Electron-doped SrTiO3
• Recombination kinetics of a dense electron-hole plasma in strontium titanate
• Time-resolved photoluminescence of n-doped SrTiO_3

Cited by in corpus (3)

• Persistent photoconductivity in 2-dimensional electron gases at different oxide interfaces
• Inhomogeneity of donor doping in SrTiO3 substrates studied by fluorescence-lifetime imaging microscopy
• Electrical Degradation in Dielectric and Piezoelectric Oxides: Review of Defect Chemistry and Associated Characterization Techniques